1. Field of the Invention
The present invention relates to a head coil arrangement of the type having a housing in or on which a number of coil elements are arranged.
2. Description of the Prior Art
Head coil arrangements of this type are known and are used in magnetic resonance devices as high-frequency transmitting and receiving coils. If the coils operate in a receiving mode, the size of the coils in relation to the size of the examination subject plays a decisive role in the resulting signal-to-noise ratio. The signal-to-noise ratio is optimal if the coils rest as close as possible to the surface of the subject, in this case the head.
This is particularly critical when capturing images of regions close to the patient's neck, such as the cerebellum for example. Due to the widely varying neck shapes of different patients, for example thick necks, thin necks, short necks, long necks, etc., it is particularly difficult to achieve a suitable shape with the closest possible proximity to the patient's head.
It is known how to produce a head coil arrangement with a coil with a fixed neck shape. This is disadvantageous however, since the fixed neck shape may come into contact with the subject at a location that is too high for some patients, which may lead to pressure marks or an uncomfortable positioning of the head. On the other hand, the fixed neck shape may extend too low for other patients, leading to poor signal intensity because of the larger-than-optimal spacing that then exists. A further disadvantage of a fixed neck shape of this kind is that the position of the head within the head coil arrangement is fixed, with the result that an individual positioning of the head is not possible.
Particularly when developing new head coil arrangements with a relatively large number of individual coils, it is necessary to bring the individual coils close to the region of the body to be examined, because, due to the relatively small coils, the intensity of the receiving signal is lower and a poorer signal-to-noise ratio is thus achieved with the same spacing.